This invention relates to the repair of a hollow viscus organ or vessel using a catheter based system to deploy an appliance, such as a bendable clip, and more particularly to minimally invasive correction of venous insufficiency for correction of incompetent venous valves.
An unresolved need exists for the repair of certain incompetent or damaged human body components, such as certain viscous organs, body lumens and cavities, for example, a damaged blood vessel or an incompetent vein valve. More particularly, chronic venous insufficiency is a problem caused by hydrodynamic forces acting on the lowest part of the body, the legs, ankles and feet. As the veins dilate due to increased pressure, the valves in the veins become less able to withstand the weight of the blood above them. This causes the veins to dilate further and the valves in the veins to fail, i.e., become incompetent. Venous valves are typically bicuspid valves, with each cusp forming a sack or reservoir for blood which, under pressure, forces the free edges of the cusps together to prevent retrograde flow of the blood and allow only antegrade flow to the heart. When an incompetent valve attempts to close in response to a pressure gradient across the valve, the cusps do not seal properly and retrograde flow of blood occurs.
Incompetence in the venous system can result from vein dilation, which causes the veins to swell with additional blood. Separation of the cusps of the venous valve at the commissure may occur as a result. The leaflets are stretched by the dilation of the vein and concomitant increase in the vein diameter which the leaflets traverse. Stretching of the leaflets of the venous valve results in redundancy which allows the leaflets to fold on themselves and leave the valve open. This is called prolapse, which can allow reflux of blood in the vein. Eventually the venous valve fails, thereby increasing the strain and pressure on the lower venous sections and overlying tissues.
Chronic venous insufficiency consists of venous hypertension of the lower limb in the deep, perforating and often superficial veins with associated pigmentation, pain, swelling and ulceration. Existing treatments for chronic venous insufficiency are less than ideal. The only known therapies currently available include elevation of the legs for extended periods, elastic support hose to compress the veins externally and surgical repair or replacement of the vein and valves. These methods are variably effective. In addition, a physician has no efficacious drugs at his disposal, and the surgeon does not have ready access to artificial venous valves. Moreover, the use of reconstructive surgery is impeded by the delicate nature and irreversible damage of the valvular structures.
Prior known prostheses include artificial venous valves and artificial valves for the heart and other anatomy which are adaptable for use in a vein. One such disclosed venous valve is comprised of an annular support member or ring defining an opening therethrough, including leaflets hingedly attached to the support ring for opening and closing the support ring opening in a manner permitting substantially unidirectional flow therethrough. Such valves are designed to be sutured or sewn into place within a blood vessel during a lengthy open surgery.
Also known is a cuff for restoring competence to an incompetent venous valve which consists of a band of biocompatible implantable material that is not stretchable at blood flow pressures. The band is of sufficient length to encompass a vein at the sight of a vein valve with the ends of the band overlapping. In one form of attachment, a first end of the band passes over a loop in a second end and is stapled thereto. The cuff is placed around a vein at the site of the incompetent valve and the diameter of the vein at the valve site is reduced until competency of the vein valve is restored.
Certain conventional surgical endoscopic, and laparoscopic procedures utilize staples or clips for repair of incisions or wounds, implantation of prostheses, anastomoses and the like. For example, surgical staples have been disclosed comprising angled and arcuate central and leg regions which can be flattened by a stapling tool having an anvil and driving structure. One such staple has been disclosed with side portions curved substantially in the form of an arc of a circle to prevent tearing of tissue by producing puncture channels.
Various forms of stapling tools also have been disclosed. One such surgical instrument consists of an anvil adapted to lie flush with the skin, a cartridge containing a plurality of staples and a U-shaped pusher for bending the staples around the anvil. Such instruments typically have mechanical actuators within a handle mechanism for positioning the staples and activating the driver or pusher against the staple and anvil.
Laparoscopic procedures have also used staples, balloons and clip appliers or staple guns for procedures such as cholecystostomies, ligation and hernia repair. Such systems have heretofore not been known to be disclosed for intraluminally repairing blood vessels or vein valves. Such limitations apparently are the result of clip and applier design. Thus, there is a need for a minimally invasive system for intraluminal repair of a body organ, lumen or cavity, for example, a blood vessel or a vein valve, using a catheter based system for deploying a bendable clip appliance.
To provide consistency with the common usage of terms used in the medical surgical arts in the United States, the terms "proximal and distal" are used with a certain meaning within the present specification. "Proximal" refers to a location of an element of the apparatus, such as a catheter, housing or wire, which is closest to the user (physician) and closest to the portion of the apparatus outside or exterior of the patient. Similarly, for the catheter elements, "distal" refers to the point farthest from the user and typically most interior to the body or lumen. With blood vessels and venous valves, "proximal" refers to a portion closest to the heart, and "distal" refers to a portion furthest from the heart.